Aeronautical propeller



Oct. 26 1926.

REED

AERO NAUTICAL PROPELLER Filed May 12 1924 ATTORNEY Patented on. 26, 1926. 1

UNITED STATES I 1,604,757 PATENT oFFIc SYLVANUS A. REED, NEW YORK, N. Y., ASSIGNOR TO THE REED PROPELLER CO. INC., OF NEW YORK, N. Y., A. CORPORATION OF NEW YORK.

AERONAUTICAL PROPELLER.

Application filed May 12, 1924. Serial No. 712,645.

This invention relates generally to propellers for aeronautical purposes and it is'well adapted for use in connection with metal propellersr In my U. S. Patent No. 1, 463,556, dated July '31, 1923, and also in my Patent No. 1,518,410, dated Dec. 9, 1924, I disclose certain types of metal aeronautical propellers, and my present improvements are also applicable to said-general type, but, of course,

are not in any way limited thereto.

In metal aeronautical propellers, and especially those of the solid type with thin sections and also those with separate blades at tached to a metal hub and of the general types shown in some of my other applications for patents, one of the principal problems is to reduce the aggregate weight, and my present invention pertains to improvements in central construction of blades and attaching hub, which result in a considerable reduction in weight over previous constructions. The centrifugal force exerted in the operation of aeronautical propellers isvery hlgh being seldom less than eight or ten tons on each blade, and the types of blade attachment' familiar in fans and blowers of low centrifugal force, are not practical for aeronautical propellers, especially under the stress of long continued-service. One part of my improvements includes means for attachingthe separate blades directly to the hub by a-peculiar interhooking of the parts, so that as regards centrifugal force, the connections are independent of bolts, rivets, sockets,

screw-threads, welds, clamps or other secondary means. Another feature of my novel attaching means is that it is limited solely by the bending moment, and shearing stress of a no wide and evenly distributed part of the blade at its strongest part, and more specifically stated the construction and arrangement is the inter-hooking of hooks bent up from the blade material, with suitably engaging members or lugs on the driving member or hub.

With these and other objects in View, my invention-will be more fully described, 11-

lustrated in the drawings and then particushown as detached.

Fig. 3, is a perspective view of one of the blades shown as detached.

Fig. 4, is a. perspective view of modified form of my invention.

Referring to the drawings, 1 is a hollow body preferably cylindrical in form and constitutes the attaching member or hub, and is provided. with the usual key-way 2, for securing said member to the drive-shaft which is not shown.

Upon the exterior of the member 1, and

preferably integral therewith, are arranged a series of pairs of anchor parts or lugs 3, 4, and 5, 6, and 7, 8, the lugs 3, 4 and 5 of each pair being disposed near one'end of the hub, while the others are located near the other end. Each pair of lugs is designed to engage with a pair of hooks on the inner ends of the respective propeller blades 9, 10 and 11. The lugs or fins are shown as angular and somewhat wedge-shaped, but the'blade-hooks may be formed or have a twist so that said fins may be rectangular or other shape, and the free or un-engaged face of each fin may blend gradually into-the wall of the member 1, to give added strength thereto, as indicated by the gradually curved surface at 12. I The separate blades 9, 10 and 11, are preferably of solid metal and are suitably shaped and provided with the desired itch-angles. The inner or root end of each lade, which is the'thickest part, is made relatively wide and has the center of its inner edge notched at 13, to provide the prongs 0r tongues 14 and 15, which are bent at 16, and 17, respectively, in opposite directions as shown in Fig. 8. The base 16 and 17 of each hooked prong thus formed is comparatively long as and the strength thereof is dependent upon the bending moment and the shearing stress of the strongest part of the blade, the metal for which is especially adapted to this structure, because of its tensile strength'fielastic limit and other physical properties, aluminum alloys, and particularly duralumin being well adapted for this use. I

The inner end of each blade bears against the exterior of the hub l on a diagonal or helical line and the engaging lugs are accordingly in staggered positions, as shown in Fig. 2. Considering now that the hooks or prongs 14 and 15, of blade 9, are in engagement with lugs 3 and 4, it will be noted 1m that hook 14 engages the right side of lug 3, while the oppositely projecting hook 15 engages its lug 4;, upon the left hand side thereof. The same arrangement is true of the other two blades 10 and 11, and their inter-engaging lugs.

lugs and integral hooks of the blades do thls work.

The books '14 and 15, and also the osi- ,tionin lugs on the hub 1, are either or 0th 'provi ed with'slots for the passage of the olts 18. In Fig. 2, the lugs are shown as provided with the bolt-slots 31, while in Fig. 3, the hooks are shown as formed with slots 30. These slots permit of a shifting or alteration in the blade an Ice when desired, by 'merel loosening t e bolts and turnin retain the adjustment, after resetting or changingthe fill'erblocks to accommodate the new angle.

In Fig. 4., I show a modification of my inventionby using two oppositely extending propeller blades 20 and 21. In this structure, the inner or root portion of each blade is notched at its edge at 22, so as to provide two substantial and strong prongs or hooks 23 and 24, which are alike and which are first bent slightly at 25, to sition the hook and then bent more sharp y at 26, to

'provide the beak for engaging the re ective ugs or fins 28 and 29, a pair of w ich is located upon opposite sides of the hub.

In each case the inner end of each blade between the hookswor prongs'abuts on and crosses the driving-axis at an angle substantially appropriate for the desired pitch of the blade. The fitting of the abutting edges of the inner edge of each blade against the surface of the hub 1, may be so snug and intimate as to cause the same. to participate in the transmission of thrust Which is malnly the duty of the hooks and lugs, for it will be noted that there is an extended contact 7 between said abutting parts and that the line of the same is diagonal 'withrespect to the exterior of said hub. Obviously this intimacy of these abutting parts may be increased b letting the end-edge of the blade sink slig tly into the surface of the hubmember, and the latter may be grooved for that purpose. I p

The construction and formation of the propeller blades and their itch angles may be in accordance with the escriptions given in my said patent and pending application for patent. though other forms may he used ith the particular improvements herein disthe bla es slightly on their longi-' tudina axes and then resetting the bolts to without, however, departing from the spirit of my invention.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. An aeronautical propeller including separate blades having hub-straddling inner ends, a hub in straddling engagement with said blades, and hook members mounted on said inner ends of the blades, and said hub being provided with blade-attaching means spaced apart diagonally thereon and engaged by said hook-members for transmission of torque and thrust.

2.'A'n aeronautical propeller includin separate blades having hook-members forme on the blade root portions and a driving member having lug-members formed inv I tegrally thereon for anchoring engagement with said hook-members, the lug-members engaged by the hook-members of an one blade being spaced apart longitudina y of and disposed on different longitudinal lines of said driving-member.

3. An aeronautical ropeller including separable blades and a dri ing-member, the inner ends of said blades bein forked and the fork-prongs being arrange to be placed in straddling relation to the driving-member, and hook means for securing the fork prongs to said driving-member.-

4. An aeronautical propeller including separable blades and a hub, the root portions of the blades being forked and the forkprongs being arranged tobe placed in diagonall straddling relation to the hub, and lugs integrally formed on said hub arranged to be placed in anchoring engagement withsaid fork-prongs.

5. An aeronautical propeller including separable blades and a hub, the root portions of the blades being forked and hooked and the fork-prongs being arranged to be placed vtogether topermit of angular displacement of the blades for varying the pitch thereof.

7. An aeronautical propeller including separable blades and ahub,-the root ortions of the blades being forked and t e fork prongs being hooked and arranged to be:

placed in diagonally straddling relation to the hub, and lugs in erently on said hub arranged to engage said fork prongs and means for adjustably securing said fork prongs and said lugs together to permit of angular displacement of the blades for causing pitch 0 ange of said blades.

8. In aeronautical propeller construction, separate blades, a driving-member provided with blade-attaching means spaced apart peripherally and longitudinally of said driv 10 ing-member for each blade, said blades each my hand.

having its root portion provided with attaching-projections spaced apart substantially in the direction of the width of the blade and constructed and arranged to be placed in engagement with said blade-attaching means on the driving-member.

In testimony whereof, I have hereunto set SYLVANUS A. REED. 

